I just finished wiring a garage for a Customer that recently moved from the UK. He mentioned that he brought with him many new power tools and that he wanted to know if they could be operated on US power system. I checked with Bosch Tools, they assured me that all of their tools are rated 50/60hz. The European voltage as I understand it is 240VAC and more specifically 240VAC between the "hot" current carrying conductor and the "neutral" grounded conductor. My question...since both systems (US and UK) have a 240VAC potential between conductors will the power tools operate? If not - please set me straight. Thanks, Mike

Slow down, there .....

First off, British jobsites often have 12ov systems ... with both legs 'hot'. These tools ought to work reasonable well on our usual circuits.

There ought to be service shops that will rewind the motors, if necessary. Such shops certainly exist "over there." The rpm difference can be a major factor in the performance of some tools.

Generally, I would suggest just replacing the tools with appropriate US models. This can't always be done; Bisch, in particular, has a number of tools for which no similar type is available in the USA.

If the voltage is nominally correct I don't see the problem. Most tools with brushes in them will run on DC (universal motor). Cord caps will be the problem. US guys, remember blue is neutral.

While the British job site tools are 110V gronded centertap (ie 55V to ground), residential tools are all typically 240V.
Tools with induction motors will run at a faster speed, which may or may not be a problem. They usually work fine and will cool a little better, due to the highter internal fan speed. Brush universal motors; they are not usually too picky about frequency, many will even run on DC. There could be a problem with the variable speed controls though.
Additionally, many of the european tools are designed to treat both leads as hot. Remember Schuko plugs(continental Europe) are not polarized. (I know that BS1363 plugs are, but because most EU tools are marketed to the entire EU usually the manufacturers will simply market the exact same tool with different plugs.) Therefore they are usually made for nonpolarized applications. So while US 240V is hot to hot vs Hot to neutral it still should not make much difference.

I have several resistive appliances in my kitchen that were purchased overseas with the intent of using them here. For one my kettle is 3600 Watts and boils water lickety-split, another (the toaster) brought over due to the desire for higher wattage appliances not avail. here. I have a specific 240v outlet wired in the kitchen, looks like this:

http://www.leviton.com/OA_HTML/ibcGetAttachment.jsp?cItemId=TRvdyGrUAqKaCh65pbMWcA&label=IBE&appName=IBE&sitex=10021:22372:US

I suppose you could do this with an European power strip: http://www.geocities.com/wa2ise/radios/eupwr.jpg So he dosn't have to change all the plugs on the tools. The plugs this strip accepts looks to not prevent neutral and hot from being plugged in backwards. So both current carrying wires being hot with 120V should not be an issue, as mentioned in a post above.

Two voltages are used for power tools in the UK

For normal tools, used on sites etc they're 110V 50Hz (centre tapped with two hots) connected via a local transformer.

The plugs look like this: (EN 60309:1999)


Some power tools may be 230V 50Hz (normal European voltage)

Industrial / professional 230V tools will have a plug like :

(EN 60309:1999)

Power tools intended for use in a residential setting will simply have a normal UK residential BS1363 plug on the end.

I can relate to the kettle thing. Mine is only 2400W though(UK model). I would love to have a 3.6KW unit.

When living in the USA, all of my South African/British power tools worked just fine on US 240V circuits - in fact the grinder ran much smoother. I used to fit double pole switches to pillar drill outlets etc. so I could isolate them before changing belts/bits etc. rather than constant unplugging.

In fact, connecting a European power tool to US 240V would be hardly different from connecting it to a 133/230V system still used in some countries (supposedly Belgium, certainly parts of Germany in the Berlin area) where single phase appliances are connected across 2 phases of a 3 phase wye system (supposedly Germany even had corner grounded 220V delta systems in some areas). So indeed, the voltage wouldn't matter at all, these tools have to be useable on 230V phase to ground as well as 230V phase to phase.
In fact even electric ranges come with a variety of possible jumper settings allowing them to be used on 230V single phase, 3 phases of a 133/230V system (always tempted to write 127/220V as per the pre-harmonization standard) and 230/400V 3 phases + Neutral (all elements connected phase to neutral), sometimes even 230V single phase 2 hots 2 neutrals (effectively feeding the range with two individual single phase circuits).

Good point about the 127/220V systems wired phase to phase, in some places. I had forgotten to mention them.
Didn't the Netherlands (or was it Norway?) use systems like that at one point, as well.

127/220V systems were common in Europe until the 1950s as 127V bulbs and appliances vanished from the market and any existing systems were modified to provide 220V using hot-to-hot to bring them into line with the 220V 50Hz standard.

These systems pretty much followed a similar wiring arrangement to modern US systems i.e. you had 127V circuits for lighting and small appliances and 220V for heavier appliances.

In some systems, 127V and 220V were metered differently! The 127V supply used exclusively for lighting and charged at a lower rate to compete with the gas companies.

After WWII there was a huge rebuild of power infrastructure in Europe as vast amounts of it, particularly the distribution and transmission systems were destroyed. At that stage, most of the local power companies ended up being nationalised to allow major re-organisation and re-building of networks.

At that stage, everything was standardised at 220V 50Hz which had already become the de facto standard and was the most common system in use (the UK opted for 240V 50Hz for some reason...).

The old split phase systems were simply abandoned.

They remain in use in some former European colonies e.g. you can find 127V in service in parts of the Caribbean, some countries in the middle east and far east etc.

In Europe it was just considered to be of no practical advantage to have two voltages in a home. 127V doesn't really provide any great safety advantage over 220V and it makes wiring more complicated and creates complications in the appliance markets too i.e. you had to know if your appliance was 220V or 127V, rather than just buying any appliance and plugging in and it works. There is also a preference for TN-C grounding and a dislike of floating neutrals. So, in general hot+hot socket outlets are not allowed in modern building. Hence the demise of 127V

Standardisation towards 230V happened in the 80s and 90s to bring the UK, Cyprus and Malta into line with the rest of the European Area (not just the EU).

Northern Ireland has used 230V 50Hz for decades as it sat between Great Britain (240V) and the Republic of Ireland (220V) and appliances from both areas ended up on the market up there. So, it made sense.

230V 50Hz is now the nominal voltage for low voltage supplies in Europe.

Some more details to djk's overview.

1. In rural areas of Belgium 3 x 230 V TT is still pretty common (no neutral, no ground supplied). RCD is therefore mandatory. Personally I know a lot of those installations in the area of Eupen (very East).

2. Also in Germany there are a few transformers left, some of them private owned ones. They usually provide 3 x 230/133 TN as described above, 133 not in use anymore.

3. In Central Europe two voltages (now 230V/400V)remained very common, being typically used for oven/ranges. But only Swiss appliances are only 400V, other ususally use a Y arrangement and 230V for the heatings.

Typical home installation here in Ireland would be 230V 50Hz and depending on the age of the installation and the size of the home the main fuse will be either rated at:

50 amps (very old)
63 amps (old)
80 amps (modern)
or
100 amps (modern)

63amp supplies are pretty widespread though.

3 phase is rare in homes, although it does exist. You'd need a specific reason to have it e.g. a workshop or, sometimes for spreading the load on large electric heating systems (rare!)

TN-C-S is the preferred system and the most common by far, although TT exists, but it's typically single phase and supplied with a neutral, the neutral is just not connected to earth locally and would not be considered safe to bond to. Typically, those kinds of supplies tend to be found in rural areas or sometimes in old overhead urban systems.

I've noticed a lot of newer ovens meant to be installed anywhere in Europe accept various supplies i.e. simple single phase + neutral or various 3-phase configurations. In reality the oven elements only run on 230V regardless of which way you connect them up they don't use 400V at all, just split the load over the phases available

I had an old flat some years back which had been converted from 220 V phase-phase to 220V phase - neutral. Strange looking setup with two main switches, one no longer in use and all fuses in pairs, with one unused in each pair. Sure enough, when I put the voltmeter across the main fuse and its abandoned twin, I measured 400V. I presume the wires had simply been moved in the fuse box when the utility changed to voltage from 12/220 to 220/380V.

This has been the situation in Australia for many years; domestic electric ranges can be configured for single or two phase operation. There is a shorting strap connected across the phase terminals when only a single phase supply is used. Of course, being a resistive load, whether the two 240V feeds are in phase or not doesn't matter. Two and three phase supplies to houses are fairly common here so many ranges take advantage of this.

Wouldn't you still need a neutral for the controls on the appliance?

Not really, there's nothing inherent about the neutral that makes it special to controls or any other components. It's conveninent to use lower voltages where higher power levels aren't required, but the controls work just fine at 220V, and 220V is just as easily transformed to 12V as 120.

Most definitely! If the neutral went missing you'd get some bizarre effects; for one thing none of the elements would get the correct voltage, and more than one element would have to be switched on to get anything at all. Timer motors and oven lamps would not be happy with 415V across their terminals.

In the spirit of compromise, I suggest that the entire world chnge over to 165v, 55hz electricity.

A global standard? Crazy talk!

Ahh OK, 165V would be FAR too low here.
I doubt there will ever be a standard voltage the world over, John, especially when you consider you guys are still using imperial electricity, as opposed to our metric electricity, it is the future!

Not necessarily a contradiction - several German systems supplied a PEN along with the two or three phases of a 127/220V system which was solely used as a ground. Of course this only allowed/allows for TN-C-S and not TN-C (IMO about the most dangerous invention in the history of electricity).

I think mostly systems were standardized at 220/380V to allow for the use of standardized larger motors and other true 3 phase appliances in small workshops and other light commercial locations. Today, even many DIY appliances (garden mulchers, table saws,...) are available in more powerful 400V versions.

Switzerland seems to be the only country with ranges that use 400V elements connected phase to phase, more modern ones with a neutral supplied for control and lighting circuits. All others (except commercial models) are 230V only internally and can be used with any combination providing these. New ranges are supplied with a bunch of copper jumpers and the installer has to make sure they are connected to match the existing supply. These terminals are typically L1, L2, L3, N, N, PE and have to be jumpered according to the present supply. For example a 230/400V install would jumper terminals 4 and 5 and connect them to the neutral wire, the others to the corresponding phases. 230V single phase operation: jumper the aforementioned as well as 1, 2 and 3 connecting them to the phase wire, et cetera.

Steve, our voltages work in a different way down here.
How can you discount a conductor like a neutral as not necessary?

If the appliance is designed to have a neutral, yes, you need a neutral or it won't work right. If it's designed to operate off 2 wires, then it doesn't matter.

Given the odd ratio involved with three phase power, the only practical way to make a resistive element appliance work on either single phase or three phase is to have 3 elements that provide 1/3 of the heating. They are wired parallel for single phase, and star (wye) for three phase (including possibly without the neutral attached). Dual voltage single phase (as in North America) has the option to use 2 elements in either parallel for the lower voltage or series for the higher voltage (and the neutral is not needed unless its 2 phases of a 3 phase system). So there are a lot of possible wiring options, and a neutral is no always necessary. But having elements designed for direct phase to phase connection (whether three phase or single phase) sacrifices alternatives.

Something tells me that warranty claims on ranges in Switzerland might be a bit higher than the norm with connection options like that. We are lucky to get DIY's to provide a strain-relief, connector, bushing, etc. for final connections to appliances. I don't even want to think of the thousands of improperly grounded ranges and dryers that are out there due to their thinking "a ground is a neutral and a neutral is a ground".

The options described are not Swiss but rather apply to most other Continental European countries. Switzerland doesn't offer that many options, they connect the elements phase to phase, either all elements between two phases or split over all 3 phases.
In Austria ranges are simply not designed to be installed by DIYers and largely it seems to work. I didn't connect too many myself but the new ones I installed came without any connections made, forcing the installer to install the provided jumpers in the necessary positions. Schematics are printed right next to the terminals.

So ranges in Europe are hardwired via whips like HVAC equipment and water heaters in the US?

I can't say for all of Europe, but all of the ones I've seen in Scotland are.

UK cooking appliances are a little different to US ones in that often people have 2 seperate parts:

The oven part, single ovens are usually rated at 3kW and can be plugged in. Double ovens 4-5kW would be hard-wired on their own circuit but should have an isolator above the counter.

The top bit where the pans go are often 7-8kW and are always hardwired, also with an isolator


The more traditional cooker, all in one is always wired on its own circuit, usually in 6mm on a 30a breaker/fuse Mine is like this and is 13.5kW

The cable used to connect the appliance to the outlet plate is the standard Twin and Earth cable

Traditionally, a special Cooker Connection Unit was installed and you would often see the cable going to this in trunking. Slightly more recently, another part, the outlet plate is installed behind the cooker

Both ways are available in the US, either separate oven and cooktop (hob) or combined in one unit.

Combined is popular because it tracks back to old wood stoves that had hot plates on top and a baking chamber next to the burner. Combined can be inconvenient because of the maximum of 50 amps, or in some cases 60 amps, of available current (at 240 volts). So this limits the size if the tops are all electric.

Separate is ultimately more convenient if you have the kitchen space to separate them. And the circuit requirements, being split, or more modest.

I personally do not like glass tops because of the difficult of getting quick high heat. Spiral elements are somewhat better, but not a whole lot. Gas has traditionally worked best for cooking, but electric is still useful for low simmering after fast heating.

The latest thing I found is the induction cooktop. It works with traditional steel woks when the induction surface is made rounded to match (these are called "induction woks"). Combined with high wattage (2.4kW to 3.8kW) this appears to do as well as a gas fired wok. It would need a 15 to 20 amp circuit at 240V, or 10 amps at 400V.

So my future kitchen is probably going to be a real mixup. But things should be on separate circuits not greater than 30A each at 240V (they frown on people getting 480/277V or 416/240V at home here).

Yep, except for some rare countries (I think Sweden) they always are and homeowners are not supposed to do any electrical work involving tools (i.e. beyond plugging and unplugging stuff or replacing light bulbs). So I guess if a range were damaged by miswiring the manufacturer could easily claim illegal installation and refuse to pay.
It is legal though to connect ranges via an appropriate 3 phase plug and I will certainly do so whenever I install one in the future as these plugs and receptacles are just much nicer to wire as the traditional cord outlets (ranges are considered portable appliances even though hard wired and have to be wired using a flexible cord whip and wall outlet with proper strain relief).

Edit: both separate and combined are available here. If separate usually the oven is plugged in (3.5 kW, within the limits of a 230V general purpose 16A circuit) and the hob is hard wired using 2 phases of a 3 phase circuit. Sometimes they only appear to be split but actually the hob is just fed via the oven and the oven gets the same feed as a combined range. Internally combined ranges usually have the top elements wired to two of the 3 phases and the oven to the third.

Johno,
I'd like you to clarify that power rating?
3kW seems a tad low for an "appliance" that has a grill element in it, over here a grill element can be rated as high as 5-6kW.
Don't get me wrong, I'm not trying to take you to task or anything, it's been a while since I fixed an oven.
I was always told the main reason for a stove having such a large supply cable, was because of the Grill element.

Hi,

It is only the single ovens that are 3kW, like this one: Oven

I guess I'm a bit out of date re US cookers then! Probably all those old films

That's typical of US ovens and ranges. Individual electric range elements in the US are typically between around 1000W - 2400W, (1200-1500W for a standard coil element) with the stove element around 3000W or so. A typical 40A 240V breaker will support 9.6kW total between them all.

Larger building sites can have 3-phase transformers instead of 110V CTE (Center-Tap Earth). The secondary is 63/110V wye, star point grounded, but no neutral extended, with single-phase 110V branches being distributed A-B, A-C, and B-C as required.

Cooking appliances have also become quite a lot more energy efficient in recent years than they used to be. However, the main thing is that modern kitchens tend not to use the traditional "cooker" i.e. double oven, grill + 4 hobs.

The current trend here is two single ovens mounted at eye level side-by-side rather than the traditional double oven.

Also, one that Paul might be interested in, ETCI banned the use of ring circuits to supply socket circuits in kitchens here in the most recent update to the Irish wiring regulations. For historical reasons, the ring circuit is far less widely used here than it is in the UK anyway, but even so it was permitted.

Rings can still be used, but only on low-power socket circuits i.e. to non-kitchen/utility room areas.

Seems like a sensible enough approach to me.

If someone has a reference to this, they might consider updating the wikipedia reference to Ring circuits.

http://en.wikipedia.org/wiki/Ring_main

They way our regulation system works, the new rules are phased in over a period of 12 months.

ET101:2008 (4th Edition) of the Irish National Rules for Electrical Installations became available on 06 October 2008. However, new installations may be constructed to either the 3rd or 4th editions until 30 September 2009. In the mean time the industry is supposed to re-educate itself about the new rules.

As soon as I get my hands on a copy, I'll reference the appropriate sections on here and on wikipedia.

Well, not being a fan of rings I'm fine with that, but why not remove them from the rules entirely? I really don't see the point of disallowing them for higher-power circuits and still retaining them for all the general-purpose outlets which these days are feeding just TVs, computers, cordless phone base units, etc. around the house.